Efficient zero-based decompression

ABSTRACT

A processor core including a hardware decode unit to decode vector instructions for decompressing a run length encoded (RLE) set of source data elements and an execution unit to execute the decoded instructions. The execution unit generates a first mask by comparing set of source data elements with a set of zeros and then counts the trailing zeros in the mask. A second mask is made based on the count of trailing zeros. The execution unit then copies the set of source data elements to a buffer using the second mask and then reads the number of RLE zeros from the set of source data elements. The buffer is shifted and copied to a result and the set of source data elements is shifted to the right. If more valid data elements are in the set of source data elements this is repeated until all valid data is processed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application is a continuation application claimingpriority from U.S. patent application Ser. No. 13/991,858, whose §371(c) date is Jun. 5, 2013, and titled: “Efficient Zero-BasedDecompression”, which is a U.S. National Phase Application under 35U.S.C. § 371 of International Application No. PCT/US2011/068226, filedDec. 30, 2011, and titled: “Efficient Zero-Based Decompression”, both ofwhich are incorporated herein by reference in their entirety.

FIELD

The field of invention relates generally to computer processorarchitecture, and, more specifically, to an efficient zero baseddecompression.

BACKGROUND

An instruction set, or instruction set architecture (ISA), is the partof the computer architecture related to programming, and may include thenative data types, instructions, register architecture, addressingmodes, memory architecture, interrupt and exception handling, andexternal input and output (I/O). It should be noted that the terminstruction generally refers herein to a macro-instruction—that isinstructions that are provided to the processor for execution—as opposedto micro-instructions or micro-ops—that result from a processor'sdecoder decoding macro-instructions). The instruction set architectureis distinguished from the microarchitecture, which is the internaldesign of the processor implementing the ISA. Processors with differentmicroarchitectures can share a common instruction set.

An instruction set includes one or more instruction formats. A giveninstruction format defines various fields (number of bits, location ofbits) to specify, among other things, the operation to be performed andthe operand(s) on which that operation is to be performed. A giveninstruction is expressed using a given instruction format and specifiesthe operation and the operands. An instruction stream is a specificsequence of instructions, where each instruction in the sequence is anoccurrence of an instruction in an instruction format.

Scientific, financial, auto-vectorized general purpose, RMS(recognition, mining, and synthesis)/visual and multimedia applications(e.g., 2D/3D graphics, image processing, videocompression/decompression, voice recognition algorithms and audiomanipulation) often require the same operation to be performed on alarge number of data items (referred to as “data parallelism”). SingleInstruction Multiple Data (SIMD) refers to a type of instruction thatcauses a processor to perform the same operation on multiple data items.SIMD technology is especially suited to processors that can logicallydivide the bits in a register into a number of fixed-sized dataelements, each of which represents a separate value. For example, thebits in a 64-bit register may be specified as a source operand to beoperated on as four separate 16-bit data elements, each of whichrepresents a separate 16-bit value. As another example, the bits in a256-bit register may be specified as a source operand to be operated onas four separate 64-bit packed data elements (quad-word (Q) size dataelements), eight separate 32-bit packed data elements (double word (D)size data elements), sixteen separate 16-bit packed data elements (word(W) size data elements), or thirty-two separate 8-bit data elements(byte (B) size data elements). This type of data is referred to as thepacked data type or vector data type, and operands of this data type arereferred to as packed data operands or vector operands. In other words,a packed data item or vector refers to a sequence of packed dataelements; and a packed data operand or a vector operand is a source ordestination operand of a SIMD instruction (also known as a packed datainstruction or a vector instruction).

By way of example, one type of SIMD instruction specifies a singlevector operation to be performed on two source vector operands in avertical fashion to generate a destination vector operand (also referredto as a result vector operand) of the same size, with the same number ofdata elements, and in the same data element order. The data elements inthe source vector operands are referred to as source data elements,while the data elements in the destination vector operand are referredto a destination or result data elements. These source vector operandsare of the same size and contain data elements of the same width, andthus they contain the same number of data elements. The source dataelements in the same bit positions in the two source vector operandsform pairs of data elements (also referred to as corresponding dataelements; that is, the data element in data element position 0 of eachsource operand correspond, the data element in data element position 1of each source operand correspond, and so on). The operation specifiedby that SIMD instruction is performed separately on each of these pairsof source data elements to generate a matching number of result dataelements, and thus each pair of source data elements has a correspondingresult data element. Since the operation is vertical and since theresult vector operand is the same size, has the same number of dataelements, and the result data elements are stored in the same dataelement order as the source vector operands, the result data elementsare in the same bit positions of the result vector operand as theircorresponding pair of source data elements in the source vectoroperands. In addition to this exemplary type of SIMD instruction, thereare a variety of other types of SIMD instructions (e.g., that have onlyone or has more than two source vector operands; that operate in ahorizontal fashion; that generate a result vector operand that is of adifferent size, that have a different size of data elements, and/or thathave a different data element order). It should be understood that theterm destination vector operand (or destination operand) is defined asthe direct result of performing the operation specified by aninstruction, including the storage of that destination operand at alocation (be it a register or at a memory address specified by thatinstruction) so that it may be accessed as a source operand by anotherinstruction (by specification of that same location by the anotherinstruction.

Certain instruction set architectures allow multiple vector and scalaroperations to complete in parallel and update the instruction setarchitecture register set. These instruction set architectures can beleveraged to implement compression/decompression instructions andalgorithms such as instructions based on run-length encoding (RLE).

RLE is a form of lossless data compressing where sequences of data in astream of data are compressed when those sequences contain one or moresets of consecutive data values. Rather than storing each data elementin the set of consecutive data values, a single element with the valueis stored followed by an element with the count of consecutive elements.This form of compression is most useful on data that contains many suchruns.

For example, zero-based compression/decompression takes advantage offrequently occurring zero elements in data streams. In some data types,particularly data associated with graphics processing, it is common tohave a significant portion of data contain the value zero and, in turn,many runs of zeros. RLE based on zero is often referred to as zero-basedcompression. Although other RLE schemes may be based on value other thanzero if compression would benefit from another RLE value being selected.

FIG. 1 illustrates a prior art method for decompressing a zero-basedstream. FIG. 1 starts with setting variable, such as a variable namedINDEX, to zero in operation 100. Flow moves from 100 to 110 where it isdetermined whether the stream still has valid input. If there is no morevalid input in the source stream then the flow is done in 190. If thereis valid input, then flow moves to operation 110 where a source elementat the position indicated by the index is read into a variable, such asa temporary variable named TEMP; TEMP=SOURCE[INDEX]. Flow moves tooperation 115 where the index is incremented, INDEX=INDEX+1, and then tooperation 120 where it is determined whether TEMP is equal to 0;TEMP==INDEX. If TEMP is not equal to zero, then the operation moves to122 where TEMP is output as being decompressed. If TEMP is equal to zerothen the flow moves to operation 125 where the contents of the sourcestream at the position indicated by the index, which as previouslyincremented, are read into a variable named COUNT; COUNT=SOURCE[INDEX].The COUNT variable now holds the run length for the decompression of 0.Flow moves from 125 to operation 127 where INDEX is incremented,INDEX=INDEX+1, then to operation 130 where a second index, e.g. INDEX2,is set to 0. From here flow moves to a small loop that checks whetherINDEX2 is less than COUNT at operation 135, outputs TEMP at operation140, increments INDEX2 as operation 145, and then repeats from 135 untilINDEX2 is no longer less than COUNT, meaning that the number of zerosindicated by the run length have been output. Once the correct number ofzeros has been output, flow moves back to operation 105 and continuesuntil there is no more valid input. This form of decompression is highlyiterative and involves a data element by data element evaluation of theinput stream to output non-zero values and convert a zero value/countpair into an output stream.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdescription and accompanying drawings that are used to illustrateembodiments of the invention. In the drawings:

FIG. 1 illustrates a prior art method for decompressing a zero-basedstream;

FIG. 2 illustrates an exemplary flow for run length decoding accordingto one embodiment;

FIG. 3 illustrates an exemplary operation of the method shown in FIG. 2according to one sample input;

FIG. 4a illustrates an exemplary AVX instruction format including a VEXprefix, real opcode field, Mod R/M byte, SIB byte, displacement field,and IMM8 according to one embodiment;

FIG. 4B illustrates which fields from FIG. 4A make up a full opcodefield and a base operation field according to one embodiment;

FIG. 4C illustrates which fields from FIG. 4A make up a register indexfield according to one embodiment;

FIG. 5A is a block diagram illustrating a generic vector friendlyinstruction format and class A instruction templates thereof accordingto embodiments of the invention;

FIG. 5B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention

FIG. 6A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention;

FIG. 6B is a block diagram illustrating the fields of the specificvector friendly instruction format of FIG. 6a that make up the fullopcode field according to one embodiment of the invention;

FIG. 6C is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the register index fieldaccording to one embodiment of the invention;

FIG. 6D is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the augmentationoperation field according to one embodiment of the invention;

FIG. 7 is a block diagram of a register architecture according to oneembodiment of the invention;

FIG. 8A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention;

FIG. 8B is a block diagram illustrating both an exemplary embodiment ofan in-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention;

FIG. 9A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network and with its local subsetof the Level 2 (L2) cache, according to embodiments of the invention;

FIG. 9B is an expanded view of part of the processor core in FIG. 9Aaccording to embodiments of the invention;

FIG. 10 is a block diagram of a processor that may have more than onecore, may have an integrated memory controller, and may have integratedgraphics according to embodiments of the invention;

FIG. 11 is a block diagram of a system in accordance with one embodimentof the present invention;

FIG. 12 is a block diagram of a first more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 13 is a block diagram of a second more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 14 is a block diagram of a SoC in accordance with an embodiment ofthe present invention; and

FIG. 15 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention.

DESCRIPTION OF EMBODIMENTS

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the invention may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail inorder not to obscure the understanding of this description.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Rather than rely on an inefficient scalar implementation such asdescribed in FIG. 1, embodiments of the invention make use of a vectorbased instruction set architecture. Thus, rather than use expensiveshuffle and permute instructions, simple shifts and masked moves areutilized to more efficiently decompressed RLE data. Furthermore, whiledescribed with reference to zero-based RLE data, a different compressionvalue, may be used for run length encoding and then used as the valuethat is decoded with a run length pair.

FIG. 2 illustrates an exemplary flow for run length decoding accordingto one embodiment. Flow begins at operation 200 with initializing twovariables to 0, a result variable named RES and an insertion pointvariable named IP. Flow moves to operation 205 with generating a masknamed M by comparing the source SRC elements to a set of elementscomprising the value that was RLE; e.g. comparing SRC to a set of 0s.Flow moves to operation 210 with counting the number of trailing zerosin the mask M and storing the value in a variable named K. From thereflow moves to operation 215 with generation of a second mask named Pthat contains K 1s. The flow continues to operation 220 by performing amasked copy of source into a variable named TMP with the mask P. Theflow then moves to operation 225 where the number of 0s is read from theelement indexed by [K+1] in the source SRC. The variable TMP is leftshifted based on IP at operation 230 to align TMP with the currentposition of the RES variable. At operation 235, TMP is copied into RESwith an OR operation such that previously set values, from previousiterations, in RES are maintained while the newly copied values from theSRC that were put in TMP can be copied. From here, the flow continues atoperation 240 where the insertion point IP is updated by adding K+N tothe current IP. Next flow is moved to operation 245 where the source SRCif right shifted K+2 elements to remove previously processed values.Flow moves to operation 250 where it is determined whether the flow isdone. If so, the flow moves to operation 255 with outputting the resultRES. If not, the flows iterates back to operation 205.

In one embodiment of the invention, each operation is performed by asingle instruction in an execution unit such as a vector execution unit.For example, certain vector instruction set architectures contain singleinstructions for generating a mask vector by comparing a source operandwith a set of comparison values, such as a corresponding vector all setto 0. Still further, the same vector instruction set architectures maycomprise an instruction for counting the number of consecutive zeros atthe end of a source vector (i.e. the trailing zero count of a sourcevector register). While in other embodiments, one or more operations areperformed by a single instruction for performing that operation. Stillin further embodiments, each operation is performed by two or moreinstructions used in conjunction to perform said operation.

FIG. 3 illustrates an exemplary operation of the method shown in FIG. 2according to one sample input. FIG. 3 is illustrated with four columns.The first column, most left hand column, is titled OP and each row islabeled with operations from FIG. 2 to indicate where in processing therows correspond with. The following columns are titled iteration A,iteration B, and iteration C as the given input required 3 iterations.In the illustrated example, the source input SRC is shown as a stream of8 data elements. However, it should be noted that the methods describedare not limited to any particular number or width of data elements. Forexample, the operations described could work with κ one-byte dataelements or 16 32-bit data elements equally and would only be limitedbased on the architecture of the processor and/or memory used to executesaid operations.

In FIG. 3, the source SRC 300 is set to 0, 6, 2, 0, 9, 3, 0, 4. This isa zero-based RLE value that will decode to 6, 0, 0, 9, 0, 0, 0, 4. Atoperation 200 in iteration A, the result RES 305 is set to 0, 0, 0, 0,0, 0, 0, 0 and the insertion point IP 310 is set to 0. At operation 205in iteration A, a mask M 315A is generated by comparing the SRC 300 to aset of 0s. This yields a mask M 315A as 1, 0, 0, 1, 0, 0, 1, 0 with a 1in each position where the SRC 300 contained a 0. The number of trailingzeros, zeros at the far right of the mask M 315A, are counted at 210 andplaced into a count K 320A as 1 trailing zero. At operation 215 ofiteration A, a mask P 325A is generated with K 0s, such that mask P 325Acontains 0, 0, 0, 0, 0, 0, 0, 1. At operation 220 a masked copy of thesource SRC 300 is performed using mask P 325A to generate a TMP buffer330A that contains 0, 0, 0, 0, 0, 0, 0, 4. Then in 225 of iteration A,the number of zeros N 335A is read from element K+1 of the source SRC300, which is 3. In 230 of iteration A, the TMP buffer 330A is leftshifted IP 310 times to align the TMP buffer 330A with the currentposition of the result RES 305. In 235 of iteration A, the TMP buffer330A is copied into the result RES 305 using an OR operation to preservepreviously set values in the result RES 305. At operation 240 ofiteration A, the insertion point IP 310 is updated by adding K 320A andN 335A to IP 310; in iteration A, IP is set to 4 which is 0 (IP)+1 (K)+3(N). In operation 245 the source if right shifted K 320A+2 times, initeration A this is a right shift of 3, making source SRC 300 set to 0,0, 0, 0, 6, 2, 0, 9. At 250 in iteration A, it is determined that morevalid input exists and the next iteration should be ran.

Execution then continues back at operation 205 in iteration B. Now theSRC 300 is set to 0, 0, 0, 0, 6, 2, 0, 9. The result RES 305 iscurrently set to 0, 0, 0, 0, 0, 0, 0, 4 and the insertion point IP 310is set to 4. At operation 205 in iteration B, a mask M 315B is generatedby comparing the SRC 300 to a set of 0s. This yields a mask M 315B as 1,1, 1, 1, 0, 0, 1, 0 with a 1 in each position where the SRC 300contained a 0. The number of trailing zeros, zeros at the far right ofthe mask M 315B, are counted at 210 and placed into a count K 320B as 1trailing zero. At operation 215 of iteration B, a mask P 325B isgenerated with K 0s, such that mask P 325B contains 0, 0, 0, 0, 0, 0,0, 1. At operation 220 a masked copy of the source SRC 300 is performedusing mask P 325B to generate a TMP buffer 330B that contains 0, 0, 0,0, 0, 0, 0, 9. Then in 225 of iteration B, the number of zeros N 335B isread from element K+1 of the source SRC 300, which is 2. In 230 ofiteration B, the TMP buffer 330B is left shifted IP 310 times to alignthe TMP buffer 330B with the current position of the result RES 305,this yields a TMP buffer of 0, 0, 0, 9, 0, 0, 0, 0. In 235 of iterationB, the TMP buffer 330B is copied into the result RES 305 using an ORoperation to preserve previously set values in the result RES 305,yielding a result RES 300 of 0, 0, 0, 9, 0, 0, 0, 4 at iteration B. Atoperation 240 of iteration B, the insertion point IP 310 is updated byadding K 320B and N 335B to IP 310; in iteration B, IP is set to 7 whichis 4 (IP)+1 (K)+2 (N). In operation 245 the source if right shifted K320B+2 times, in iteration B this is a right shift of 3 yielding asource SRC 300 of 0, 0, 0, 0, 0, 0, 0, 6. At 250 in iteration B, it isdetermined that more valid input exists and the next iteration should beran.

Execution then continues back at operation 205 in iteration C. Now theSRC 300 is set to 0, 0, 0, 0, 0, 0, 0, 6. The result RES 305 iscurrently set to 0, 0, 0, 9, 0, 0, 0, 4 and the insertion point IP 310is set to 7. At operation 205 in iteration C, a mask M 315C is generatedby comparing the SRC 300 to a set of 0s. This yields a mask M 315C as 1,1, 1, 1, 1, 1, 1, 0 with a 1 in each position where the SRC 300contained a 0. The number of trailing zeros, zeros at the far right ofthe mask M 315C, are counted at 210 and placed into a count K 320C as 1trailing zero. At operation 215 of iteration C, a mask P 325C isgenerated with K 0s, such that mask P 325C contains 0, 0, 0, 0, 0, 0,0, 1. At operation 220 a masked copy of the source SRC 300 is performedusing mask P 325C to generate a TMP buffer 330C that contains 0, 0, 0,0, 0, 0, 0, 6. Then in 225 of iteration C, the number of zeros N 335C isread from element K+1 of the source SRC 300, which is 0. In 230 ofiteration C, the TMP buffer 330C is left shifted IP 310 times to alignthe TMP buffer 330C with the current position of the result RES 305,this yields a TMP buffer of 6, 0, 0, 0, 0, 0, 0, 0. In 235 of iterationC, the TMP buffer 330C is copied into the result RES 305 using an ORoperation to preserve previously set values in the result RES 305,yielding a result RES 300 of 6, 0, 0, 9, 0, 0, 0, 4 at iteration C. Atoperation 240 of iteration C, the insertion point IP 310 is updated byadding K 320C and N 335C to IP 310; in iteration C, IP is set to 8 whichis 7 (IP)+1 (K)+0 (N). In operation 245 the source if right shifted K320C+2 times, in iteration C this is a right shift of 2 yielding asource SRC 300 of 0, 0, 0, 0, 0, 0, 0, 0. At 250 in iteration C, it isdetermined that no more valid input exists and that the result RES 305of 6, 0, 0, 9, 0, 0, 0, 4 should be output in operation 255.

Exemplary Instruction Formats

Embodiments of the instruction(s) described herein may be embodied indifferent formats. Additionally, exemplary systems, architectures, andpipelines are detailed below. Embodiments of the instruction(s) may beexecuted on such systems, architectures, and pipelines, but are notlimited to those detailed.

VEX Instruction Format

VEX encoding allows instructions to have more than two operands, andallows SIMD vector registers to be longer than 128 bits. The use of aVEX prefix provides for three-operand (or more) syntax. For example,previous two-operand instructions performed operations such as A=A+B,which overwrites a source operand. The use of a VEX prefix enablesoperands to perform nondestructive operations such as A=B+C.

FIG. 4A illustrates an exemplary AVX instruction format including a VEXprefix 402, real opcode field 430, Mod R/M byte 440, SIB byte 450,displacement field 462, and IMM8 472. FIG. 4B illustrates which fieldsfrom FIG. 4A make up a full opcode field 474 and a base operation field442. FIG. 4C illustrates which fields from FIG. 4A make up a registerindex field 444.

VEX Prefix (Bytes 0-2) 402 is encoded in a three-byte form. The firstbyte is the Format Field 440 (VEX Byte 0, bits [7:0]), which contains anexplicit C4 byte value (the unique value used for distinguishing the C4instruction format). The second-third bytes (VEX Bytes 1-2) include anumber of bit fields providing specific capability. Specifically, REXfield 405 (VEX Byte 1, bits [7-5]) consists of a VEX.R bit field (VEXByte 1, bit [7]-R), VEX.X bit field (VEX byte 1, bit [6]-X), and VEX.Bbit field (VEX byte 1, bit[5]-B). Other fields of the instructionsencode the lower three bits of the register indexes as is known in theart (rrr, xxx, and bbb), so that Rrrr, Xxxx, and Bbbb may be formed byadding VEX.R, VEX.X, and VEX.B. Opcode map field 415 (VEX byte 1, bits[4:0]-mmmmm) includes content to encode an implied leading opcode byte.W Field 464 (VEX byte 2, bit [7]-W)—is represented by the notationVEX.W, and provides different functions depending on the instruction.The role of VEX.vvvv 420 (VEX Byte 2, bits [6:3]-vvvv) may include thefollowing: 1) VEX.vvvv encodes the first source register operand,specified in inverted (1s complement) form and is valid for instructionswith 2 or more source operands; 2) VEX.vvvv encodes the destinationregister operand, specified in 1s complement form for certain vectorshifts; or 3) VEX.vvvv does not encode any operand, the field isreserved and should contain 1111b. If VEX.L 468 Size field (VEX byte 2,bit [2]-L)=0, it indicates 128 bit vector; if VEX.L=1, it indicates 256bit vector. Prefix encoding field 425 (VEX byte 2, bits [1:0]-pp)provides additional bits for the base operation field.

Real Opcode Field 430 (Byte 3) is also known as the opcode byte. Part ofthe opcode is specified in this field.

MOD R/M Field 440 (Byte 4) includes MOD field 442 (bits [7-6]), Regfield 444 (bits [5-3]), and R/M field 446 (bits [2-0]). The role of Regfield 444 may include the following: encoding either the destinationregister operand or a source register operand (the rrr of Rrrr), or betreated as an opcode extension and not used to encode any instructionoperand. The role of R/M field 446 may include the following: encodingthe instruction operand that references a memory address, or encodingeither the destination register operand or a source register operand.

Scale, Index, Base (SIB)—The content of Scale field 450 (Byte 5)includes SS 452 (bits [7-6]), which is used for memory addressgeneration. The contents of SIB.xxx 454 (bits [5-3]) and SIB.bbb 456(bits [2-0]) have been previously referred to with regard to theregister indexes Xxxx and Bbbb.

The Displacement Field 462 and the immediate field (IMM8) 472 containaddress data.

Exemplary Encoding into VEX

Generic Vector Friendly Instruction Format

A vector friendly instruction format is an instruction format that issuited for vector instructions (e.g., there are certain fields specificto vector operations). While embodiments are described in which bothvector and scalar operations are supported through the vector friendlyinstruction format, alternative embodiments use only vector operationsthe vector friendly instruction format.

FIGS. 5A-5B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments of the invention. FIG. 5A is a block diagram illustrating ageneric vector friendly instruction format and class A instructiontemplates thereof according to embodiments of the invention; while FIG.5B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments of the invention. Specifically, a generic vector friendlyinstruction format 500 for which are defined class A and class Binstruction templates, both of which include no memory access 505instruction templates and memory access 520 instruction templates. Theterm generic in the context of the vector friendly instruction formatrefers to the instruction format not being tied to any specificinstruction set.

While embodiments of the invention will be described in which the vectorfriendly instruction format supports the following: a 64 byte vectoroperand length (or size) with 32 bit (4 byte) or 64 bit (8 byte) dataelement widths (or sizes) (and thus, a 64 byte vector consists of either16 doubleword-size elements or alternatively, 8 quadword-size elements);a 64 byte vector operand length (or size) with 16 bit (2 byte) or 8 bit(1 byte) data element widths (or sizes); a 32 byte vector operand length(or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit (2 byte), or 8bit (1 byte) data element widths (or sizes); and a 16 byte vectoroperand length (or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit(2 byte), or 8 bit (1 byte) data element widths (or sizes); alternativeembodiments may support more, less and/or different vector operand sizes(e.g., 256 byte vector operands) with more, less, or different dataelement widths (e.g., 128 bit (16 byte) data element widths).

The class A instruction templates in FIG. 5A include: 1) within the nomemory access 505 instruction templates there is shown a no memoryaccess, full round control type operation 510 instruction template and ano memory access, data transform type operation 515 instructiontemplate; and 2) within the memory access 520 instruction templatesthere is shown a memory access, temporal 525 instruction template and amemory access, non-temporal 530 instruction template. The class Binstruction templates in FIG. 5B include: 1) within the no memory access505 instruction templates there is shown a no memory access, write maskcontrol, partial round control type operation 512 instruction templateand a no memory access, write mask control, vsize type operation 517instruction template; and 2) within the memory access 520 instructiontemplates there is shown a memory access, write mask control 527instruction template.

The generic vector friendly instruction format 500 includes thefollowing fields listed below in the order illustrated in FIGS. 5A-5B.

Format field 540—a specific value (an instruction format identifiervalue) in this field uniquely identifies the vector friendly instructionformat, and thus occurrences of instructions in the vector friendlyinstruction format in instruction streams. As such, this field isoptional in the sense that it is not needed for an instruction set thathas only the generic vector friendly instruction format.

Base operation field 542—its content distinguishes different baseoperations.

Register index field 544—its content, directly or through addressgeneration, specifies the locations of the source and destinationoperands, be they in registers or in memory. These include a sufficientnumber of bits to select N registers from a P×Q (e.g. 32×512, 16×128,32×1024, 64×1024) register file. While in one embodiment N may be up tothree sources and one destination register, alternative embodiments maysupport more or less sources and destination registers (e.g., maysupport up to two sources where one of these sources also acts as thedestination, may support up to three sources where one of these sourcesalso acts as the destination, may support up to two sources and onedestination).

Modifier field 546—its content distinguishes occurrences of instructionsin the generic vector instruction format that specify memory access fromthose that do not; that is, between no memory access 505 instructiontemplates and memory access 520 instruction templates. Memory accessoperations read and/or write to the memory hierarchy (in some casesspecifying the source and/or destination addresses using values inregisters), while non-memory access operations do not (e.g., the sourceand destinations are registers). While in one embodiment this field alsoselects between three different ways to perform memory addresscalculations, alternative embodiments may support more, less, ordifferent ways to perform memory address calculations.

Augmentation operation field 550—its content distinguishes which one ofa variety of different operations to be performed in addition to thebase operation. This field is context specific. In one embodiment of theinvention, this field is divided into a class field 568, an alpha field552, and a beta field 554. The augmentation operation field 550 allowscommon groups of operations to be performed in a single instructionrather than 2, 3, or 4 instructions.

Scale field 560—its content allows for the scaling of the index field'scontent for memory address generation (e.g., for address generation thatuses 2 scale*index+base).

Displacement Field 562A—its content is used as part of memory addressgeneration (e.g., for address generation that uses 2scale*index+base+displacement).

Displacement Factor Field 562B (note that the juxtaposition ofdisplacement field 562A directly over displacement factor field 562Bindicates one or the other is used)—its content is used as part ofaddress generation; it specifies a displacement factor that is to bescaled by the size of a memory access (N)—where N is the number of bytesin the memory access (e.g., for address generation that uses 2scale*index+base+scaled displacement). Redundant low-order bits areignored and hence, the displacement factor field's content is multipliedby the memory operands total size (N) in order to generate the finaldisplacement to be used in calculating an effective address. The valueof N is determined by the processor hardware at runtime based on thefull opcode field 574 (described later herein) and the data manipulationfield 554C. The displacement field 562A and the displacement factorfield 562B are optional in the sense that they are not used for the nomemory access 505 instruction templates and/or different embodiments mayimplement only one or none of the two.

Data element width field 564—its content distinguishes which one of anumber of data element widths is to be used (in some embodiments for allinstructions; in other embodiments for only some of the instructions).This field is optional in the sense that it is not needed if only onedata element width is supported and/or data element widths are supportedusing some aspect of the opcodes.

Write mask field 570—its content controls, on a per data elementposition basis, whether that data element position in the destinationvector operand reflects the result of the base operation andaugmentation operation. Class A instruction templates supportmerging-writemasking, while class B instruction templates support bothmerging- and zeroing-writemasking. When merging, vector masks allow anyset of elements in the destination to be protected from updates duringthe execution of any operation (specified by the base operation and theaugmentation operation); in other one embodiment, preserving the oldvalue of each element of the destination where the corresponding maskbit has a 0. In contrast, when zeroing vector masks allow any set ofelements in the destination to be zeroed during the execution of anyoperation (specified by the base operation and the augmentationoperation); in one embodiment, an element of the destination is set to 0when the corresponding mask bit has a 0 value. A subset of thisfunctionality is the ability to control the vector length of theoperation being performed (that is, the span of elements being modified,from the first to the last one); however, it is not necessary that theelements that are modified be consecutive. Thus, the write mask field570 allows for partial vector operations, including loads, stores,arithmetic, logical, etc. While embodiments of the invention aredescribed in which the write mask field's 570 content selects one of anumber of write mask registers that contains the write mask to be used(and thus the write mask field's 570 content indirectly identifies thatmasking to be performed), alternative embodiments instead or additionalallow the mask write field's 570 content to directly specify the maskingto be performed.

Immediate field 572—its content allows for the specification of animmediate. This field is optional in the sense that is it not present inan implementation of the generic vector friendly format that does notsupport immediate and it is not present in instructions that do not usean immediate.

Class field 568—its content distinguishes between different classes ofinstructions. With reference to FIGS. 5A-B, the contents of this fieldselect between class A and class B instructions. In FIGS. 5A-B, roundedcorner squares are used to indicate a specific value is present in afield (e.g., class A 568A and class B 568B for the class field 568respectively in FIGS. 5A-B).

Instruction Templates of Class A

In the case of the non-memory access 505 instruction templates of classA, the alpha field 552 is interpreted as an RS field 552A, whose contentdistinguishes which one of the different augmentation operation typesare to be performed (e.g., round 552A.1 and data transform 552A.2 arerespectively specified for the no memory access, round type operation510 and the no memory access, data transform type operation 515instruction templates), while the beta field 554 distinguishes which ofthe operations of the specified type is to be performed. In the nomemory access 505 instruction templates, the scale field 560, thedisplacement field 562A, and the displacement scale filed 562B are notpresent.

No-Memory Access Instruction Templates—Full Round Control Type Operation

In the no memory access full round control type operation 510instruction template, the beta field 554 is interpreted as a roundcontrol field 554A, whose content(s) provide static rounding. While inthe described embodiments of the invention the round control field 554Aincludes a suppress all floating point exceptions (SAE) field 556 and around operation control field 558, alternative embodiments may supportmay encode both these concepts into the same field or only have one orthe other of these concepts/fields (e.g., may have only the roundoperation control field 558).

SAE field 556—its content distinguishes whether or not to disable theexception event reporting; when the SAE field's 556 content indicatessuppression is enabled, a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler.

Round operation control field 558—its content distinguishes which one ofa group of rounding operations to perform (e.g., Round-up, Round-down,Round-towards-zero and Round-to-nearest). Thus, the round operationcontrol field 558 allows for the changing of the rounding mode on a perinstruction basis. In one embodiment of the invention where a processorincludes a control register for specifying rounding modes, the roundoperation control field's 550 content overrides that register value.

No Memory Access Instruction Templates—Data Transform Type Operation

In the no memory access data transform type operation 515 instructiontemplate, the beta field 554 is interpreted as a data transform field554B, whose content distinguishes which one of a number of datatransforms is to be performed (e.g., no data transform, swizzle,broadcast).

In the case of a memory access 520 instruction template of class A, thealpha field 552 is interpreted as an eviction hint field 552B, whosecontent distinguishes which one of the eviction hints is to be used (inFIG. 5A, temporal 552B.1 and non-temporal 552B.2 are respectivelyspecified for the memory access, temporal 525 instruction template andthe memory access, non-temporal 530 instruction template), while thebeta field 554 is interpreted as a data manipulation field 554C, whosecontent distinguishes which one of a number of data manipulationoperations (also known as primitives) is to be performed (e.g., nomanipulation; broadcast; up conversion of a source; and down conversionof a destination). The memory access 520 instruction templates includethe scale field 560, and optionally the displacement field 562A or thedisplacement scale field 562B.

Vector memory instructions perform vector loads from and vector storesto memory, with conversion support. As with regular vector instructions,vector memory instructions transfer data from/to memory in a dataelement-wise fashion, with the elements that are actually transferred isdictated by the contents of the vector mask that is selected as thewrite mask.

Memory Access Instruction Templates—Temporal

Temporal data is data likely to be reused soon enough to benefit fromcaching. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Memory Access Instruction Templates—Non-Temporal

Non-temporal data is data unlikely to be reused soon enough to benefitfrom caching in the 1st-level cache and should be given priority foreviction. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Instruction Templates of Class B

In the case of the instruction templates of class B, the alpha field 552is interpreted as a write mask control (Z) field 552C, whose contentdistinguishes whether the write masking controlled by the write maskfield 570 should be a merging or a zeroing.

In the case of the non-memory access 505 instruction templates of classB, part of the beta field 554 is interpreted as an RL field 557A, whosecontent distinguishes which one of the different augmentation operationtypes are to be performed (e.g., round 557A.1 and vector length (VSIZE)557A.2 are respectively specified for the no memory access, write maskcontrol, partial round control type operation 512 instruction templateand the no memory access, write mask control, VSIZE type operation 517instruction template), while the rest of the beta field 554distinguishes which of the operations of the specified type is to beperformed. In the no memory access 505 instruction templates, the scalefield 560, the displacement field 562A, and the displacement scale filed562B are not present.

In the no memory access, write mask control, partial round control typeoperation 510 instruction template, the rest of the beta field 554 isinterpreted as a round operation field 559A and exception eventreporting is disabled (a given instruction does not report any kind offloating-point exception flag and does not raise any floating pointexception handler).

Round operation control field 559A—just as round operation control field558, its content distinguishes which one of a group of roundingoperations to perform (e.g., Round-up, Round-down, Round-towards-zeroand Round-to-nearest). Thus, the round operation control field 559Aallows for the changing of the rounding mode on a per instruction basis.In one embodiment of the invention where a processor includes a controlregister for specifying rounding modes, the round operation controlfield's 550 content overrides that register value.

In the no memory access, write mask control, VSIZE type operation 517instruction template, the rest of the beta field 554 is interpreted as avector length field 559B, whose content distinguishes which one of anumber of data vector lengths is to be performed on (e.g., 128, 256, or512 byte).

In the case of a memory access 520 instruction template of class B, partof the beta field 554 is interpreted as a broadcast field 557B, whosecontent distinguishes whether or not the broadcast type datamanipulation operation is to be performed, while the rest of the betafield 554 is interpreted the vector length field 559B. The memory access520 instruction templates include the scale field 560, and optionallythe displacement field 562A or the displacement scale field 562B.

With regard to the generic vector friendly instruction format 500, afull opcode field 574 is shown including the format field 540, the baseoperation field 542, and the data element width field 564. While oneembodiment is shown where the full opcode field 574 includes all ofthese fields, the full opcode field 574 includes less than all of thesefields in embodiments that do not support all of them. The full opcodefield 574 provides the operation code (opcode).

The augmentation operation field 550, the data element width field 564,and the write mask field 570 allow these features to be specified on aper instruction basis in the generic vector friendly instruction format.

The combination of write mask field and data element width field createtyped instructions in that they allow the mask to be applied based ondifferent data element widths.

The various instruction templates found within class A and class B arebeneficial in different situations. In some embodiments of theinvention, different processors or different cores within a processormay support only class A, only class B, or both classes. For instance, ahigh performance general purpose out-of-order core intended forgeneral-purpose computing may support only class B, a core intendedprimarily for graphics and/or scientific (throughput) computing maysupport only class A, and a core intended for both may support both (ofcourse, a core that has some mix of templates and instructions from bothclasses but not all templates and instructions from both classes iswithin the purview of the invention). Also, a single processor mayinclude multiple cores, all of which support the same class or in whichdifferent cores support different class. For instance, in a processorwith separate graphics and general purpose cores, one of the graphicscores intended primarily for graphics and/or scientific computing maysupport only class A, while one or more of the general purpose cores maybe high performance general purpose cores with out of order executionand register renaming intended for general-purpose computing thatsupport only class B. Another processor that does not have a separategraphics core, may include one more general purpose in-order orout-of-order cores that support both class A and class B. Of course,features from one class may also be implement in the other class indifferent embodiments of the invention. Programs written in a high levellanguage would be put (e.g., just in time compiled or staticallycompiled) into an variety of different executable forms, including: 1) aform having only instructions of the class(es) supported by the targetprocessor for execution; or 2) a form having alternative routineswritten using different combinations of the instructions of all classesand having control flow code that selects the routines to execute basedon the instructions supported by the processor which is currentlyexecuting the code.

Exemplary Specific Vector Friendly Instruction Format

FIG. 6A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments of the invention.FIG. 6A shows a specific vector friendly instruction format 600 that isspecific in the sense that it specifies the location, size,interpretation, and order of the fields, as well as values for some ofthose fields. The specific vector friendly instruction format 600 may beused to extend the x86 instruction set, and thus some of the fields aresimilar or the same as those used in the existing x86 instruction setand extension thereof (e.g., AVX). This format remains consistent withthe prefix encoding field, real opcode byte field, MOD R/M field, SIBfield, displacement field, and immediate fields of the existing x86instruction set with extensions. The fields from FIG. 5 into which thefields from FIG. 6A map are illustrated.

It should be understood that, although embodiments of the invention aredescribed with reference to the specific vector friendly instructionformat 600 in the context of the generic vector friendly instructionformat 500 for illustrative purposes, the invention is not limited tothe specific vector friendly instruction format 600 except whereclaimed. For example, the generic vector friendly instruction format 500contemplates a variety of possible sizes for the various fields, whilethe specific vector friendly instruction format 600 is shown as havingfields of specific sizes. By way of specific example, while the dataelement width field 564 is illustrated as a one bit field in thespecific vector friendly instruction format 600, the invention is not solimited (that is, the generic vector friendly instruction format 500contemplates other sizes of the data element width field 564).

The generic vector friendly instruction format 500 includes thefollowing fields listed below in the order illustrated in FIG. 6A.

EVEX Prefix (Bytes 0-3) 602—is encoded in a four-byte form.

Format Field 540 (EVEX Byte 0, bits [7:0])—the first byte (EVEX Byte 0)is the format field 540 and it contains 0x62 (the unique value used fordistinguishing the vector friendly instruction format in one embodimentof the invention).

The second-fourth bytes (EVEX Bytes 1-3) include a number of bit fieldsproviding specific capability.

REX field 605 (EVEX Byte 1, bits [7-5])—consists of a EVEX.R bit field(EVEX Byte 1, bit [7]-R), EVEX.X bit field (EVEX byte 1, bit [6]-X), and557BEX byte 1, bit[5]-B). The EVEX.R, EVEX.X, and EVEX.B bit fieldsprovide the same functionality as the corresponding VEX bit fields, andare encoded using is complement form, i.e. ZMM0 is encoded as 1111B,ZMM15 is encoded as 0000B. Other fields of the instructions encode thelower three bits of the register indexes as is known in the art (rrr,xxx, and bbb), so that Rrrr, Xxxx, and Bbbb may be formed by addingEVEX.R, EVEX.X, and EVEX.B.

REX′ field 510—this is the first part of the REX′ field 510 and is theEVEX.R′ bit field (EVEX Byte 1, bit [4]-R′) that is used to encodeeither the upper 16 or lower 16 of the extended 32 register set. In oneembodiment of the invention, this bit, along with others as indicatedbelow, is stored in bit inverted format to distinguish (in thewell-known x86 32-bit mode) from the BOUND instruction, whose realopcode byte is 62, but does not accept in the MOD R/M field (describedbelow) the value of 11 in the MOD field; alternative embodiments of theinvention do not store this and the other indicated bits below in theinverted format. A value of 1 is used to encode the lower 16 registers.In other words, R′Rrrr is formed by combining EVEX.R′, EVEX.R, and theother RRR from other fields.

Opcode map field 615 (EVEX byte 1, bits [3:0]-mmmm)—its content encodesan implied leading opcode byte (0F, 0F 38, or 0F 3).

Data element width field 564 (EVEX byte 2, bit [7]-W)—is represented bythe notation EVEX.W. EVEX.W is used to define the granularity (size) ofthe datatype (either 32-bit data elements or 64-bit data elements).

EVEX.vvvv 620 (EVEX Byte 2, bits [6:3]-vvvv)—the role of EVEX.vvvv mayinclude the following: 1) EVEX.vvvv encodes the first source registeroperand, specified in inverted (1s complement) form and is valid forinstructions with 2 or more source operands; 2) EVEX.vvvv encodes thedestination register operand, specified in 1s complement form forcertain vector shifts; or 3) EVEX.vvvv does not encode any operand, thefield is reserved and should contain 1111b. Thus, EVEX.vvvv field 620encodes the 4 low-order bits of the first source register specifierstored in inverted (1s complement) form. Depending on the instruction,an extra different EVEX bit field is used to extend the specifier sizeto 32 registers.

EVEX.U 568 Class field (EVEX byte 2, bit [2]-U)—If EVEX.0=0, itindicates class A or EVEX.U0; if EVEX.0=1, it indicates class B orEVEX.U1.

Prefix encoding field 625 (EVEX byte 2, bits [1:0]-pp)—providesadditional bits for the base operation field. In addition to providingsupport for the legacy SSE instructions in the EVEX prefix format, thisalso has the benefit of compacting the SIMD prefix (rather thanrequiring a byte to express the SIMD prefix, the EVEX prefix requiresonly 2 bits). In one embodiment, to support legacy SSE instructions thatuse a SIMD prefix (66H, F2H, F3H) in both the legacy format and in theEVEX prefix format, these legacy SIMD prefixes are encoded into the SIMDprefix encoding field; and at runtime are expanded into the legacy SIMDprefix prior to being provided to the decoder's PLA (so the PLA canexecute both the legacy and EVEX format of these legacy instructionswithout modification). Although newer instructions could use the EVEXprefix encoding field's content directly as an opcode extension, certainembodiments expand in a similar fashion for consistency but allow fordifferent meanings to be specified by these legacy SIMD prefixes. Analternative embodiment may redesign the PLA to support the 2 bit SIMDprefix encodings, and thus not require the expansion.

Alpha field 552 (EVEX byte 3, bit [7]-EH; also known as EVEX.EH,EVEX.rs, EVEX.RL, EVEX.write mask control, and EVEX.N; also illustratedwith α)—as previously described, this field is context specific.

Beta field 554 (EVEX byte 3, bits [6:4]-SSS, also known as EVEX.s2-0,EVEX.r2-0, EVEX.rr1, EVEX.LL0, EVEX.LLB; also illustrated with βββ)—aspreviously described, this field is context specific.

REX′ field 510—this is the remainder of the REX′ field and is theEVEX.V′ bit field (EVEX Byte 3, bit [3]-V′) that may be used to encodeeither the upper 16 or lower 16 of the extended 32 register set. Thisbit is stored in bit inverted format. A value of 1 is used to encode thelower 16 registers. In other words, V′VVVV is formed by combiningEVEX.V′, EVEX.vvvv.

Write mask field 570 (EVEX byte 3, bits [2:0]-kkk)—its content specifiesthe index of a register in the write mask registers as previouslydescribed. In one embodiment of the invention, the specific value EVEXkkk=000 has a special behavior implying no write mask is used for theparticular instruction (this may be implemented in a variety of waysincluding the use of a write mask hardwired to all ones or hardware thatbypasses the masking hardware).

Real Opcode Field 630 (Byte 4) is also known as the opcode byte. Part ofthe opcode is specified in this field.

MOD R/M Field 640 (Byte 5) includes MOD field 642, Reg field 644, andR/M field 646. As previously described, the MOD field's 642 contentdistinguishes between memory access and non-memory access operations.The role of Reg field 644 can be summarized to two situations: encodingeither the destination register operand or a source register operand, orbe treated as an opcode extension and not used to encode any instructionoperand. The role of R/M field 646 may include the following: encodingthe instruction operand that references a memory address, or encodingeither the destination register operand or a source register operand.

Scale, Index, Base (SIB) Byte (Byte 6)—As previously described, thescale field's 550 content is used for memory address generation. SIB.xxx654 and SIB.bbb 656—the contents of these fields have been previouslyreferred to with regard to the register indexes Xxxx and Bbbb.

Displacement field 562A (Bytes 7-10)—when MOD field 642 contains 10,bytes 7-10 are the displacement field 562A, and it works the same as thelegacy 32-bit displacement (disp32) and works at byte granularity.

Displacement factor field 562B (Byte 7)—when MOD field 642 contains 01,byte 7 is the displacement factor field 562B. The location of this fieldis that same as that of the legacy x86 instruction set 8-bitdisplacement (disp8), which works at byte granularity. Since disp8 issign extended, it can only address between −128 and 127 bytes offsets;in terms of 64 byte cache lines, disp8 uses 8 bits that can be set toonly four really useful values −128, −64, 0, and 64; since a greaterrange is often needed, disp32 is used; however, disp32 requires 4 bytes.In contrast to disp8 and disp32, the displacement factor field 562B is areinterpretation of disp8; when using displacement factor field 562B,the actual displacement is determined by the content of the displacementfactor field multiplied by the size of the memory operand access (N).This type of displacement is referred to as disp8*N. This reduces theaverage instruction length (a single byte of used for the displacementbut with a much greater range). Such compressed displacement is based onthe assumption that the effective displacement is multiple of thegranularity of the memory access, and hence, the redundant low-orderbits of the address offset do not need to be encoded. In other words,the displacement factor field 562B substitutes the legacy x86instruction set 8-bit displacement. Thus, the displacement factor field562B is encoded the same way as an x86 instruction set 8-bitdisplacement (so no changes in the ModRM/SIB encoding rules) with theonly exception that disp8 is overloaded to disp8*N. In other words,there are no changes in the encoding rules or encoding lengths but onlyin the interpretation of the displacement value by hardware (which needsto scale the displacement by the size of the memory operand to obtain abyte-wise address offset).

Immediate field 572 operates as previously described.

Full Opcode Field

FIG. 6B is a block diagram illustrating the fields of the specificvector friendly instruction format 600 that make up the full opcodefield 574 according to one embodiment of the invention. Specifically,the full opcode field 574 includes the format field 540, the baseoperation field 542, and the data element width (W) field 564. The baseoperation field 542 includes the prefix encoding field 625, the opcodemap field 615, and the real opcode field 630.

Register Index Field

FIG. 6C is a block diagram illustrating the fields of the specificvector friendly instruction format 600 that make up the register indexfield 544 according to one embodiment of the invention. Specifically,the register index field 544 includes the REX field 605, the REX′ field610, the MODR/M.reg field 644, the MODR/M.r/m field 646, the VVVV field620, xxx field 654, and the bbb field 656.

Augmentation Operation Field

FIG. 6D is a block diagram illustrating the fields of the specificvector friendly instruction format 600 that make up the augmentationoperation field 550 according to one embodiment of the invention. Whenthe class (U) field 568 contains 0, it signifies EVEX.U0 (class A 568A);when it contains 1, it signifies EVEX.U1 (class B 568B). When U=0 andthe MOD field 642 contains 11 (signifying a no memory access operation),the alpha field 552 (EVEX byte 3, bit [7]-EH) is interpreted as the rsfield 552A. When the rs field 552A contains a 1 (round 552A.1), the betafield 554 (EVEX byte 3, bits [6:4]-SSS) is interpreted as the roundcontrol field 554A. The round control field 554A includes a one bit SAEfield 556 and a two bit round operation field 558. When the rs field552A contains a 0 (data transform 552A.2), the beta field 554 (EVEX byte3, bits [6:4]-SSS) is interpreted as a three bit data transform field554B. When U=0 and the MOD field 642 contains 00, 01, or 10 (signifyinga memory access operation), the alpha field 552 (EVEX byte 3, bit[7]-EH) is interpreted as the eviction hint (EH) field 552B and the betafield 554 (EVEX byte 3, bits [6:4]-SSS) is interpreted as a three bitdata manipulation field 554C.

When U=1, the alpha field 552 (EVEX byte 3, bit [7]-EH) is interpretedas the write mask control (Z) field 552C. When U=1 and the MOD field 642contains 11 (signifying a no memory access operation), part of the betafield 554 (EVEX byte 3, bit [4]-S0) is interpreted as the RL field 557A;when it contains a 1 (round 557A.1) the rest of the beta field 554 (EVEXbyte 3, bit [6-5]-S2-1) is interpreted as the round operation field559A, while when the RL field 557A contains a 0 (VSIZE 557.A2) the restof the beta field 554 (EVEX byte 3, bit [6-5]-S2-1) is interpreted asthe vector length field 559B (EVEX byte 3, bit [6-5]-L1-0). When U=1 andthe MOD field 642 contains 00, 01, or 10 (signifying a memory accessoperation), the beta field 554 (EVEX byte 3, bits [6:4]-SSS) isinterpreted as the vector length field 559B (EVEX byte 3, bit[6-5]-L1-0) and the broadcast field 557B (EVEX byte 3, bit [4]-B).

Exemplary Register Architecture

FIG. 7 is a block diagram of a register architecture 700 according toone embodiment of the invention. In the embodiment illustrated, thereare 32 vector registers 710 that are 512 bits wide; these registers arereferenced as zmm0 through zmm31. The lower order 256 bits of the lower16 zmm registers are overlaid on registers ymm0-16. The lower order 128bits of the lower 16 zmm registers (the lower order 128 bits of the ymmregisters) are overlaid on registers xmm0-15. The specific vectorfriendly instruction format 600 operates on these overlaid register fileas illustrated in the below tables.

Adjustable Vector Length Class Operations Registers Instruction A (FIG.5A; 510, 515, 525, zmm registers Templates that U = 0) 530 (the vectordo not include length is 64 byte) the vector length B (FIG. 5B; 512 zmmregisters field 559B U = 1) (the vector length is 64 byte) Instruction B(FIG. 5B; 517, 527 zmm, ymm, or Templates that U = 1) xmm registers doinclude the (the vector vector length length is 64 byte, field 559B 32byte, or 16 byte) depending on the vector length field 559B

In other words, the vector length field 559B selects between a maximumlength and one or more other shorter lengths, where each such shorterlength is half the length of the preceding length; and instructionstemplates without the vector length field 559B operate on the maximumvector length. Further, in one embodiment, the class B instructiontemplates of the specific vector friendly instruction format 600 operateon packed or scalar single/double-precision floating point data andpacked or scalar integer data. Scalar operations are operationsperformed on the lowest order data element position in an zmm/ymm/xmmregister; the higher order data element positions are either left thesame as they were prior to the instruction or zeroed depending on theembodiment.

Write mask registers 715—in the embodiment illustrated, there are 8write mask registers (k0 through k7), each 64 bits in size. In analternate embodiment, the write mask registers 715 are 16 bits in size.As previously described, in one embodiment of the invention, the vectormask register k0 cannot be used as a write mask; when the encoding thatwould normally indicate k0 is used for a write mask, it selects ahardwired write mask of 0xFFFF, effectively disabling write masking forthat instruction.

General-purpose registers 725—in the embodiment illustrated, there aresixteen 64-bit general-purpose registers that are used along with theexisting x86 addressing modes to address memory operands. Theseregisters are referenced by the names RAX, RBX, RCX, RDX, RBP, RSI, RDI,RSP, and R8 through R15.

Scalar floating point stack register file (x87 stack) 745, on which isaliased the MMX packed integer flat register file 750—in the embodimentillustrated, the x87 stack is an eight-element stack used to performscalar floating-point operations on 32/64/80-bit floating point datausing the x87 instruction set extension; while the MMX registers areused to perform operations on 64-bit packed integer data, as well as tohold operands for some operations performed between the MMX and XMMregisters.

Alternative embodiments of the invention may use wider or narrowerregisters. Additionally, alternative embodiments of the invention mayuse more, less, or different register files and registers.

Exemplary Core Architectures, Processors, and Computer Architectures

Processor cores may be implemented in different ways, for differentpurposes, and in different processors. For instance, implementations ofsuch cores may include: 1) a general purpose in-order core intended forgeneral-purpose computing; 2) a high performance general purposeout-of-order core intended for general-purpose computing; 3) a specialpurpose core intended primarily for graphics and/or scientific(throughput) computing. Implementations of different processors mayinclude: 1) a CPU including one or more general purpose in-order coresintended for general-purpose computing and/or one or more generalpurpose out-of-order cores intended for general-purpose computing; and2) a coprocessor including one or more special purpose cores intendedprimarily for graphics and/or scientific (throughput). Such differentprocessors lead to different computer system architectures, which mayinclude: 1) the coprocessor on a separate chip from the CPU; 2) thecoprocessor on a separate die in the same package as a CPU; 3) thecoprocessor on the same die as a CPU (in which case, such a coprocessoris sometimes referred to as special purpose logic, such as integratedgraphics and/or scientific (throughput) logic, or as special purposecores); and 4) a system on a chip that may include on the same die thedescribed CPU (sometimes referred to as the application core(s) orapplication processor(s)), the above described coprocessor, andadditional functionality. Exemplary core architectures are describednext, followed by descriptions of exemplary processors and computerarchitectures.

Exemplary Core Architectures

In-Order and Out-of-Order Core Block Diagram

FIG. 8A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments of the invention. FIG.8B is a block diagram illustrating both an exemplary embodiment of anin-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments of the invention. The solid linedboxes in FIGS. 8A-B illustrate the in-order pipeline and in-order core,while the optional addition of the dashed lined boxes illustrates theregister renaming, out-of-order issue/execution pipeline and core. Giventhat the in-order aspect is a subset of the out-of-order aspect, theout-of-order aspect will be described.

In FIG. 8A, a processor pipeline 800 includes a fetch stage 802, alength decode stage 804, a decode stage 806, an allocation stage 808, arenaming stage 810, a scheduling (also known as a dispatch or issue)stage 812, a register read/memory read stage 814, an execute stage 816,a write back/memory write stage 818, an exception handling stage 822,and a commit stage 824.

FIG. 8B shows processor core 890 including a front end unit 830 coupledto an execution engine unit 850, and both are coupled to a memory unit870. The core 890 may be a reduced instruction set computing (RISC)core, a complex instruction set computing (CISC) core, a very longinstruction word (VLIW) core, or a hybrid or alternative core type. Asyet another option, the core 890 may be a special-purpose core, such as,for example, a network or communication core, compression engine,coprocessor core, general purpose computing graphics processing unit(GPGPU) core, graphics core, or the like.

The front end unit 830 includes a branch prediction unit 832 coupled toan instruction cache unit 834, which is coupled to an instructiontranslation lookaside buffer (TLB) 836, which is coupled to aninstruction fetch unit 838, which is coupled to a decode unit 840. Thedecode unit 840 (or decoder) may decode instructions, and generate as anoutput one or more micro-operations, micro-code entry points,microinstructions, other instructions, or other control signals, whichare decoded from, or which otherwise reflect, or are derived from, theoriginal instructions. The decode unit 840 may be implemented usingvarious different mechanisms. Examples of suitable mechanisms include,but are not limited to, look-up tables, hardware implementations,programmable logic arrays (PLAs), microcode read only memories (ROMs),etc. In one embodiment, the core 890 includes a microcode ROM or othermedium that stores microcode for certain macroinstructions (e.g., indecode unit 840 or otherwise within the front end unit 830). The decodeunit 840 is coupled to a rename/allocator unit 852 in the executionengine unit 850.

The execution engine unit 850 includes the rename/allocator unit 852coupled to a retirement unit 854 and a set of one or more schedulerunit(s) 856. The scheduler unit(s) 856 represents any number ofdifferent schedulers, including reservations stations, centralinstruction window, etc. The scheduler unit(s) 856 is coupled to thephysical register file(s) unit(s) 858. Each of the physical registerfile(s) units 858 represents one or more physical register files,different ones of which store one or more different data types, such asscalar integer, scalar floating point, packed integer, packed floatingpoint, vector integer, vector floating point, status (e.g., aninstruction pointer that is the address of the next instruction to beexecuted), etc. In one embodiment, the physical register file(s) unit858 comprises a vector registers unit, a write mask registers unit, anda scalar registers unit. These register units may provide architecturalvector registers, vector mask registers, and general purpose registers.The physical register file(s) unit(s) 858 is overlapped by theretirement unit 854 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement unit 854and the physical register file(s) unit(s) 858 are coupled to theexecution cluster(s) 860. The execution cluster(s) 860 includes a set ofone or more execution units 862 and a set of one or more memory accessunits 864. The execution units 862 may perform various operations (e.g.,shifts, addition, subtraction, multiplication) and on various types ofdata (e.g., scalar floating point, packed integer, packed floatingpoint, vector integer, vector floating point). While some embodimentsmay include a number of execution units dedicated to specific functionsor sets of functions, other embodiments may include only one executionunit or multiple execution units that all perform all functions. Thescheduler unit(s) 856, physical register file(s) unit(s) 858, andexecution cluster(s) 860 are shown as being possibly plural becausecertain embodiments create separate pipelines for certain types ofdata/operations (e.g., a scalar integer pipeline, a scalar floatingpoint/packed integer/packed floating point/vector integer/vectorfloating point pipeline, and/or a memory access pipeline that each havetheir own scheduler unit, physical register file(s) unit, and/orexecution cluster—and in the case of a separate memory access pipeline,certain embodiments are implemented in which only the execution clusterof this pipeline has the memory access unit(s) 864). It should also beunderstood that where separate pipelines are used, one or more of thesepipelines may be out-of-order issue/execution and the rest in-order.

The set of memory access units 864 is coupled to the memory unit 870,which includes a data TLB unit 872 coupled to a data cache unit 874coupled to a level 2 (L2) cache unit 876. In one exemplary embodiment,the memory access units 864 may include a load unit, a store addressunit, and a store data unit, each of which is coupled to the data TLBunit 872 in the memory unit 870. The instruction cache unit 834 isfurther coupled to a level 2 (L2) cache unit 876 in the memory unit 870.The L2 cache unit 876 is coupled to one or more other levels of cacheand eventually to a main memory.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement the pipeline 800 asfollows: 1) the instruction fetch 838 performs the fetch and lengthdecoding stages 802 and 804; 2) the decode unit 840 performs the decodestage 806; 3) the rename/allocator unit 852 performs the allocationstage 808 and renaming stage 810; 4) the scheduler unit(s) 856 performsthe schedule stage 812; 5) the physical register file(s) unit(s) 858 andthe memory unit 870 perform the register read/memory read stage 814; theexecution cluster 860 perform the execute stage 816; 6) the memory unit870 and the physical register file(s) unit(s) 858 perform the writeback/memory write stage 818; 7) various units may be involved in theexception handling stage 822; and 8) the retirement unit 854 and thephysical register file(s) unit(s) 858 perform the commit stage 824.

The core 890 may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 890includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2, and/or some form of the generic vector friendly instructionformat (U=0 and/or U=1) previously described), thereby allowing theoperations used by many multimedia applications to be performed usingpacked data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor also includes separate instruction and data cache units834/874 and a shared L2 cache unit 876, alternative embodiments may havea single internal cache for both instructions and data, such as, forexample, a Level 1 (L1) internal cache, or multiple levels of internalcache. In some embodiments, the system may include a combination of aninternal cache and an external cache that is external to the core and/orthe processor. Alternatively, all of the cache may be external to thecore and/or the processor.

Specific Exemplary In-Order Core Architecture

FIGS. 9A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip. The logic blocks communicate through a high-bandwidthinterconnect network (e.g., a ring network) with some fixed functionlogic, memory I/O interfaces, and other necessary I/O logic, dependingon the application.

FIG. 9A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network 902 and with its localsubset of the Level 2 (L2) cache 904, according to embodiments of theinvention. In one embodiment, an instruction decoder 900 supports thex86 instruction set with a packed data instruction set extension. An L1cache 906 allows low-latency accesses to cache memory into the scalarand vector units. While in one embodiment (to simplify the design), ascalar unit 908 and a vector unit 910 use separate register sets(respectively, scalar registers 912 and vector registers 914) and datatransferred between them is written to memory and then read back in froma level 1 (L1) cache 906, alternative embodiments of the invention mayuse a different approach (e.g., use a single register set or include acommunication path that allow data to be transferred between the tworegister files without being written and read back).

The local subset of the L2 cache 904 is part of a global L2 cache thatis divided into separate local subsets, one per processor core. Eachprocessor core has a direct access path to its own local subset of theL2 cache 904. Data read by a processor core is stored in its L2 cachesubset 904 and can be accessed quickly, in parallel with other processorcores accessing their own local L2 cache subsets. Data written by aprocessor core is stored in its own L2 cache subset 904 and is flushedfrom other subsets, if necessary. The ring network ensures coherency forshared data. The ring network is bi-directional to allow agents such asprocessor cores, L2 caches and other logic blocks to communicate witheach other within the chip. Each ring data-path is 1012-bits wide perdirection.

FIG. 9B is an expanded view of part of the processor core in FIG. 9Aaccording to embodiments of the invention. FIG. 9B includes an L1 datacache 906A part of the L1 cache 904, as well as more detail regardingthe vector unit 910 and the vector registers 914. Specifically, thevector unit 910 is a 16-wide vector processing unit (VPU) (see the16-wide ALU 928), which executes one or more of integer,single-precision float, and double-precision float instructions. The VPUsupports swizzling the register inputs with swizzle unit 920, numericconversion with numeric convert units 922A-B, and replication withreplication unit 924 on the memory input. Write mask registers 926 allowpredicating resulting vector writes.

Processor with Integrated Memory Controller and Graphics

FIG. 10 is a block diagram of a processor 1000 that may have more thanone core, may have an integrated memory controller, and may haveintegrated graphics according to embodiments of the invention. The solidlined boxes in FIG. 10 illustrate a processor 1000 with a single core1002A, a system agent 1010, a set of one or more bus controller units1016, while the optional addition of the dashed lined boxes illustratesan alternative processor 1000 with multiple cores 1002A-N, a set of oneor more integrated memory controller unit(s) 1014 in the system agentunit 1010, and special purpose logic 1008.

Thus, different implementations of the processor 1000 may include: 1) aCPU with the special purpose logic 1008 being integrated graphics and/orscientific (throughput) logic (which may include one or more cores), andthe cores 1002A-N being one or more general purpose cores (e.g., generalpurpose in-order cores, general purpose out-of-order cores, acombination of the two); 2) a coprocessor with the cores 1002A-N being alarge number of special purpose cores intended primarily for graphicsand/or scientific (throughput); and 3) a coprocessor with the cores1002A-N being a large number of general purpose in-order cores. Thus,the processor 1000 may be a general-purpose processor, coprocessor orspecial-purpose processor, such as, for example, a network orcommunication processor, compression engine, graphics processor, GPGPU(general purpose graphics processing unit), a high-throughput manyintegrated core (MIC) coprocessor (including 30 or more cores), embeddedprocessor, or the like. The processor may be implemented on one or morechips. The processor 1000 may be a part of and/or may be implemented onone or more substrates using any of a number of process technologies,such as, for example, BiCMOS, CMOS, or NMOS.

The memory hierarchy includes one or more levels of cache within thecores, a set or one or more shared cache units 1006, and external memory(not shown) coupled to the set of integrated memory controller units1014. The set of shared cache units 1006 may include one or moremid-level caches, such as level 2 (L2), level 3 (L3), level 4 (L4), orother levels of cache, a last level cache (LLC), and/or combinationsthereof. While in one embodiment a ring based interconnect unit 1012interconnects the integrated graphics logic 1008, the set of sharedcache units 1006, and the system agent unit 1010/integrated memorycontroller unit(s) 1014, alternative embodiments may use any number ofwell-known techniques for interconnecting such units. In one embodiment,coherency is maintained between one or more cache units 1006 and cores1002-A-N.

In some embodiments, one or more of the cores 1002A-N are capable ofmultithreading. The system agent 1010 includes those componentscoordinating and operating cores 1002A-N. The system agent unit 1010 mayinclude for example a power control unit (PCU) and a display unit. ThePCU may be or include logic and components needed for regulating thepower state of the cores 1002A-N and the integrated graphics logic 1008.The display unit is for driving one or more externally connecteddisplays.

The cores 1002A-N may be homogenous or heterogeneous in terms ofarchitecture instruction set; that is, two or more of the cores 1002A-Nmay be capable of execution the same instruction set, while others maybe capable of executing only a subset of that instruction set or adifferent instruction set.

Exemplary Computer Architectures

FIGS. 11-14 are block diagrams of exemplary computer architectures.Other system designs and configurations known in the arts for laptops,desktops, handheld PCs, personal digital assistants, engineeringworkstations, servers, network devices, network hubs, switches, embeddedprocessors, digital signal processors (DSPs), graphics devices, videogame devices, set-top boxes, micro controllers, cell phones, portablemedia players, hand held devices, and various other electronic devices,are also suitable. In general, a huge variety of systems or electronicdevices capable of incorporating a processor and/or other executionlogic as disclosed herein are generally suitable.

Referring now to FIG. 11, shown is a block diagram of a system 1100 inaccordance with one embodiment of the present invention. The system 1100may include one or more processors 1110, 1115, which are coupled to acontroller hub 1120. In one embodiment the controller hub 1120 includesa graphics memory controller hub (GMCH) 1190 and an Input/Output Hub(IOH) 1150 (which may be on separate chips); the GMCH 1190 includesmemory and graphics controllers to which are coupled memory 1140 and acoprocessor 1145; the IOH 1150 is couples input/output (I/O) devices1160 to the GMCH 1190. Alternatively, one or both of the memory andgraphics controllers are integrated within the processor (as describedherein), the memory 1140 and the coprocessor 1145 are coupled directlyto the processor 1110, and the controller hub 1120 in a single chip withthe IOH 1150.

The optional nature of additional processors 1115 is denoted in FIG. 11with broken lines. Each processor 1110, 1115 may include one or more ofthe processing cores described herein and may be some version of theprocessor 1000.

The memory 1140 may be, for example, dynamic random access memory(DRAM), phase change memory (PCM), or a combination of the two. For atleast one embodiment, the controller hub 1120 communicates with theprocessor(s) 1110, 1115 via a multi-drop bus, such as a frontside bus(FSB), point-to-point interface such as QuickPath Interconnect (QPI), orsimilar connection 1195.

In one embodiment, the coprocessor 1145 is a special-purpose processor,such as, for example, a high-throughput MIC processor, a network orcommunication processor, compression engine, graphics processor, GPGPU,embedded processor, or the like. In one embodiment, controller hub 1120may include an integrated graphics accelerator.

There can be a variety of differences between the physical resources1110, 1115 in terms of a spectrum of metrics of merit includingarchitectural, microarchitectural, thermal, power consumptioncharacteristics, and the like.

In one embodiment, the processor 1110 executes instructions that controldata processing operations of a general type. Embedded within theinstructions may be coprocessor instructions. The processor 1110recognizes these coprocessor instructions as being of a type that shouldbe executed by the attached coprocessor 1145. Accordingly, the processor1110 issues these coprocessor instructions (or control signalsrepresenting coprocessor instructions) on a coprocessor bus or otherinterconnect, to coprocessor 1145. Coprocessor(s) 1145 accept andexecute the received coprocessor instructions.

Referring now to FIG. 12, shown is a block diagram of a first morespecific exemplary system 1200 in accordance with an embodiment of thepresent invention. As shown in FIG. 12, multiprocessor system 1200 is apoint-to-point interconnect system, and includes a first processor 1270and a second processor 1280 coupled via a point-to-point interconnect1250. Each of processors 1270 and 1280 may be some version of theprocessor 1000. In one embodiment of the invention, processors 1270 and1280 are respectively processors 1110 and 1115, while coprocessor 1238is coprocessor 1145. In another embodiment, processors 1270 and 1280 arerespectively processor 1110 coprocessor 1145.

Processors 1270 and 1280 are shown including integrated memorycontroller (IMC) units 1272 and 1282, respectively. Processor 1270 alsoincludes as part of its bus controller units point-to-point (P-P)interfaces 1276 and 1278; similarly, second processor 1280 includes P-Pinterfaces 1286 and 1288. Processors 1270, 1280 may exchange informationvia a point-to-point (P-P) interface 1250 using P-P interface circuits1278, 1288. As shown in FIG. 12, IMCs 1272 and 1282 couple theprocessors to respective memories, namely a memory 1232 and a memory1234, which may be portions of main memory locally attached to therespective processors.

Processors 1270, 1280 may each exchange information with a chipset 1290via individual P-P interfaces 1252, 1254 using point to point interfacecircuits 1276, 1294, 1286, 1298. Chipset 1290 may optionally exchangeinformation with the coprocessor 1238 via a high-performance interface1239. In one embodiment, the coprocessor 1238 is a special-purposeprocessor, such as, for example, a high-throughput MIC processor, anetwork or communication processor, compression engine, graphicsprocessor, GPGPU, embedded processor, or the like.

A shared cache (not shown) may be included in either processor oroutside of both processors, yet connected with the processors via P-Pinterconnect, such that either or both processors' local cacheinformation may be stored in the shared cache if a processor is placedinto a low power mode.

Chipset 1290 may be coupled to a first bus 1216 via an interface 1296.In one embodiment, first bus 1216 may be a Peripheral ComponentInterconnect (PCI) bus, or a bus such as a PCI Express bus or anotherthird generation I/O interconnect bus, although the scope of the presentinvention is not so limited.

As shown in FIG. 12, various I/O devices 1214 may be coupled to firstbus 1216, along with a bus bridge 1218 which couples first bus 1216 to asecond bus 1220. In one embodiment, one or more additional processor(s)1215, such as coprocessors, high-throughput MIC processors, GPGPU's,accelerators (such as, e.g., graphics accelerators or digital signalprocessing (DSP) units), field programmable gate arrays, or any otherprocessor, are coupled to first bus 1216. In one embodiment, second bus1220 may be a low pin count (LPC) bus. Various devices may be coupled toa second bus 1220 including, for example, a keyboard and/or mouse 1222,communication devices 1227 and a storage unit 1228 such as a disk driveor other mass storage device which may include instructions/code anddata 1230, in one embodiment. Further, an audio I/O 1224 may be coupledto the second bus 1220. Note that other architectures are possible. Forexample, instead of the point-to-point architecture of FIG. 12, a systemmay implement a multi-drop bus or other such architecture.

Referring now to FIG. 13, shown is a block diagram of a second morespecific exemplary system 1300 in accordance with an embodiment of thepresent invention Like elements in FIGS. 12 and 13 bear like referencenumerals, and certain aspects of FIG. 12 have been omitted from FIG. 13in order to avoid obscuring other aspects of FIG. 13.

FIG. 13 illustrates that the processors 1270, 1280 may includeintegrated memory and I/O control logic (“CL”) 1272 and 1282,respectively. Thus, the CL 1272, 1282 include integrated memorycontroller units and include I/O control logic. FIG. 13 illustrates thatnot only are the memories 1232, 1234 coupled to the CL 1272, 1282, butalso that I/O devices 1314 are also coupled to the control logic 1272,1282. Legacy I/O devices 1315 are coupled to the chipset 1290.

Referring now to FIG. 14, shown is a block diagram of a SoC 1400 inaccordance with an embodiment of the present invention. Similar elementsin FIG. 10 bear like reference numerals. Also, dashed lined boxes areoptional features on more advanced SoCs. In FIG. 14, an interconnectunit(s) 1402 is coupled to: an application processor 1410 which includesa set of one or more cores 202A-N and shared cache unit(s) 1006; asystem agent unit 1010; a bus controller unit(s) 1016; an integratedmemory controller unit(s) 1014; a set or one or more coprocessors 1420which may include integrated graphics logic, an image processor, anaudio processor, and a video processor; an static random access memory(SRAM) unit 1430; a direct memory access (DMA) unit 1432; and a displayunit 1440 for coupling to one or more external displays. In oneembodiment, the coprocessor(s) 1420 include a special-purpose processor,such as, for example, a network or communication processor, compressionengine, GPGPU, a high-throughput MIC processor, embedded processor, orthe like.

Embodiments of the mechanisms disclosed herein may be implemented inhardware, software, firmware, or a combination of such implementationapproaches. Embodiments of the invention may be implemented as computerprograms or program code executing on programmable systems comprising atleast one processor, a storage system (including volatile andnon-volatile memory and/or storage elements), at least one input device,and at least one output device.

Program code, such as code 1230 illustrated in FIG. 12, may be appliedto input instructions to perform the functions described herein andgenerate output information. The output information may be applied toone or more output devices, in known fashion. For purposes of thisapplication, a processing system includes any system that has aprocessor, such as, for example; a digital signal processor (DSP), amicrocontroller, an application specific integrated circuit (ASIC), or amicroprocessor.

The program code may be implemented in a high level procedural or objectoriented programming language to communicate with a processing system.The program code may also be implemented in assembly or machinelanguage, if desired. In fact, the mechanisms described herein are notlimited in scope to any particular programming language. In any case,the language may be a compiled or interpreted language.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

Such machine-readable storage media may include, without limitation,non-transitory, tangible arrangements of articles manufactured or formedby a machine or device, including storage media such as hard disks, anyother type of disk including floppy disks, optical disks, compact diskread-only memories (CD-ROMs), compact disk rewritable's (CD-RWs), andmagneto-optical disks, semiconductor devices such as read-only memories(ROMs), random access memories (RAMs) such as dynamic random accessmemories (DRAMs), static random access memories (SRAMs), erasableprogrammable read-only memories (EPROMs), flash memories, electricallyerasable programmable read-only memories (EEPROMs), phase change memory(PCM), magnetic or optical cards, or any other type of media suitablefor storing electronic instructions.

Accordingly, embodiments of the invention also include non-transitory,tangible machine-readable media containing instructions or containingdesign data, such as Hardware Description Language (HDL), which definesstructures, circuits, apparatuses, processors and/or system featuresdescribed herein. Such embodiments may also be referred to as programproducts.

Emulation (Including Binary Translation, Code Morphing, Etc.)

In some cases, an instruction converter may be used to convert aninstruction from a source instruction set to a target instruction set.For example, the instruction converter may translate (e.g., using staticbinary translation, dynamic binary translation including dynamiccompilation), morph, emulate, or otherwise convert an instruction to oneor more other instructions to be processed by the core. The instructionconverter may be implemented in software, hardware, firmware, or acombination thereof. The instruction converter may be on processor, offprocessor, or part on and part off processor.

FIG. 15 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according to embodimentsof the invention. In the illustrated embodiment, the instructionconverter is a software instruction converter, although alternativelythe instruction converter may be implemented in software, firmware,hardware, or various combinations thereof. FIG. 15 shows a program in ahigh level language 1502 may be compiled using an x86 compiler 1504 togenerate x86 binary code 1506 that may be natively executed by aprocessor with at least one x86 instruction set core 1516. The processorwith at least one x86 instruction set core 1516 represents any processorthat can perform substantially the same functions as an Intel processorwith at least one x86 instruction set core by compatibly executing orotherwise processing (1) a substantial portion of the instruction set ofthe Intel x86 instruction set core or (2) object code versions ofapplications or other software targeted to run on an Intel processorwith at least one x86 instruction set core, in order to achievesubstantially the same result as an Intel processor with at least onex86 instruction set core. The x86 compiler 1504 represents a compilerthat is operable to generate x86 binary code 1506 (e.g., object code)that can, with or without additional linkage processing, be executed onthe processor with at least one x86 instruction set core 1516.Similarly, FIG. 15 shows the program in the high level language 1502 maybe compiled using an alternative instruction set compiler 1508 togenerate alternative instruction set binary code 1510 that may benatively executed by a processor without at least one x86 instructionset core 1514 (e.g., a processor with cores that execute the MIPSinstruction set of MIPS Technologies of Sunnyvale, Calif. and/or thatexecute the ARM instruction set of ARM Holdings of Sunnyvale, Calif.).The instruction converter 1512 is used to convert the x86 binary code1506 into code that may be natively executed by the processor without anx86 instruction set core 1514. This converted code is not likely to bethe same as the alternative instruction set binary code 1510 because aninstruction converter capable of this is difficult to make; however, theconverted code will accomplish the general operation and be made up ofinstructions from the alternative instruction set. Thus, the instructionconverter 1512 represents software, firmware, hardware, or a combinationthereof that, through emulation, simulation or any other process, allowsa processor or other electronic device that does not have an x86instruction set processor or core to execute the x86 binary code 1506.

Alternative Embodiments

While embodiments of the invention has been described in relation to ainstructions for decompressing run length encoded streams where thevalue zero is run length encoded, other embodiments may use anothervalue to be run length encoded. Therefore, embodiments of the inventionare not limited to zero-based encoding. In addition, while embodimentsof the invention have been described in relation to specificinstructions, alternative embodiments could be implemented such thatsimilar instructions, or multiple instructions, are used to achieve thesame function.

For example, while the flow diagrams in the figures show a particularorder of operations performed by certain embodiments of the invention,it should be understood that such order is exemplary (e.g., alternativeembodiments may perform the operations in a different order, combinecertain operations, overlap certain operations, etc.).

While the invention has been described in terms of several embodiments,those skilled in the art will recognize that the invention is notlimited to the embodiments described, can be practiced with modificationand alteration within the spirit and scope of the appended claims. Thedescription is thus to be regarded as illustrative instead of limiting.

What is claimed is:
 1. A method comprising: decoding a plurality ofvector instructions; and executing the plurality of decoded instructionswhich causes: generating a first mask by comparing the set of sourcedata elements to a set of zero elements comprising a same number ofelements as the set of source data elements, generating a count oftrailing zeros in the first mask, generating a second mask comprising aset of ones based on the count of trailing zeros, copying the set ofsource data elements into a first location according to the second mask,reading a number of run length encoded (RLE) zeros from a first dataelement in the set of source data elements, shifting data of the firstlocation to the left based on an insertion point; copying the data ofthe first location into a result, updating the insertion point, shiftingthe set of source data elements to the right based on the number oftrailing zeros, determining the set of source data elements contains nomore valid input, and outputting the result variable.
 2. The method ofclaim 1, wherein the first data element in the set of source dataelements is indexed in the set of source elements at a data elementlocated at an index generated by adding one to the count of trailingzeros.
 3. The method of claim 1, wherein the insertion point is updatedto a value determined by adding the insertion point, the count oftrailing zeros, and the number of RLE zeros.
 4. The method of claim 1,wherein the set of source data elements is shifted to the right a numberof times indicated by adding two to the count of trailing zeros.
 5. Themethod of claim 1, wherein the data of the first location is shifted tothe left by a number of times indicated by the value stored as theinsertion point.
 6. An article of manufacture, comprising: anon-transitory machine-readable storage medium having instructionsstored thereon; and wherein the instructions include a set of opcodes,which instruct a machine to execute the instructions and cause:generation of a first mask by comparing the set of source data elementsto a set of zero elements comprising a same number of elements as theset of source data elements; generation of a count of trailing zeros inthe first mask; generation of a second mask comprising a set of onesbased on the count of trailing zeros; a copy of the set of source dataelements into a first location according to the second mask; a number ofrun length encoded (RLE) zeros to be read from a first data element inthe set of source data elements; the data of the first location to beshifted to the left based on an insertion point; a copy of the temporarybuffer into a result; the insertion point to be updated; the set ofsource data elements to be shifted to the right based on the number oftrailing zeros; a determination of the set of source data elementscontains no more valid input; and the result variable be output.
 7. Thearticle of manufacture of claim 6, wherein the first data element in theset of source data elements is indexed in the set of source elements ata data element located at an index generated by adding one to the countof trailing zeros.
 8. The article of manufacture of claim 6, wherein theinsertion point is updated to a value determined by adding the insertionpoint, the count of trailing zeros, and the number of RLE zeros.
 9. Thearticle of manufacture of claim 6, wherein the set of source dataelements is shifted to the right a number of times indicated by addingtwo to the count of trailing zeros.
 10. The article of manufacture ofclaim 6, wherein data of the first location is shifted to the left by anumber of times indicated by the value stored in the insertion point.11. A processor core, comprising: a hardware decode circuit to decode aplurality of vector instructions; and execution engine circuitry toexecute the decoded instructions which causes: generation of a firstmask by comparing the set of source data elements to a set of zeroelements comprising a same number of elements as the set of source dataelements; generation of a count of trailing zeros in the first mask;generation of a second mask comprising a set of ones based on the countof trailing zeros; a copy of the set of source data elements into afirst location according to the second mask; a number of run lengthencoded (RLE) zeros to be read from a first data element in the set ofsource data elements; the data of the first location to be shifted tothe left based on an insertion point; a copy of the temporary bufferinto a result; the insertion point to be updated; the set of source dataelements to be shifted to the right based on the number of trailingzeros; a determination of the set of source data elements contains nomore valid input; and the result variable be output.
 12. The processorcore of claim 11, wherein the first data element in the set of sourcedata elements is indexed in the set of source elements at a data elementlocated at an index generated by adding one to the count of trailingzeros.
 13. The processor core of claim 11, wherein the insertion pointis updated to a value determined by adding the insertion point, thecount of trailing zeros, and the number of RLE zeros.
 14. The processorcore of claim 11, wherein the set of source data elements is shifted tothe right a number of times indicated by adding two to the count oftrailing zeros.
 15. The processor core of claim 11, wherein the data ofthe first location is shifted to the left by a number of times indicatedby the value stored in the insertion point.